I kinda doubt they would do this but it still sounds cool IMO.
Series 1 had a logo that was blue. Tomas
Series 2 has a logo that is red. Lucian.
Series 3 will have a logo that is green. Janus,
Cahill Files have a logo that is gray. Madrigal.
Could they make a 4th series, with a yellow logo for the Ekaterina?
I highly doubt it. One of the reasons I do is because most of the audience that loved the books are growing up and no longer are interested in it (this obviously doesn't apply to me...XD)